Less serious: cute
More serious: you can't just tell people who you're dating at that point of time. She needs to go through her own self acceptance and decide if and when she wants to come out. As for the boy, if she then lies that she was dating someone, that's a clear she doesn't want you. Just because she's not dating doesn't mean you'll always have a chance. But yes, I guess it's just part of the story to have him be really desperate.